The University of Massachusetts Flow Cytometry Center is requesting a dye laser upgrade of our FACS 440, a FACS Analyzer and a data storage and retrieval system for list mode data (Consort 30). At present our facility does not have the capability for three or four color fluorescence experiments. It will be evident after reading the individual proposals that several of our users have such needs. Our user group has also grown so large that we are requesting an analysis only instrument to remove some of the burden from the sorter. Having two instruments will also provide an important back up system should one of the instruments need repair. The third part of our request is a Consort 30 data analysis system which will allow us to acquire list mode data from either the FACS 440 or the FACS analyzer. The Consort 30 will also be useful as a computer back up should both our Harris 700 and Harris 500 computers be inoperative.